Male Reproductive System Flashcards
What are the primary male reproductive organs?
Testes (male gonads)
Scrotum
Penis
What are the accessory ducts in the male reproductive system?
Epididymis
Vas deferens
Ejaculatory duct
Urethra
What are the accessory glands in the male reproductive system?
Prostate gland
Seminal glands
Bulbo-urethral glands
What is the pathway that sperm follows to ejaculation?
Testes:
- semineferous tubules in lobules of testes
- rete testis
Epididymis
- efferent ductules
- head to body to tail
Vas deferens
- in spermatic cord in inguinal canal
Ejaculatory duct
- formed by union of vas deferens and seminal vesicles
Urethra
- prostatic, membranous, spongy
What are the contents of the spermatic cord?
- the vas deferens
- lymphatic vessels
- the testicular, ductus deferens and cremasteric arteries
- the pampinform venous plexus
- the genitofermoral nerve, and SNS, PNS and visceral afferent nerves
What are the components of the testes?
- each testes contains 250 lobules (divided by septa)
- each lobule contains 1-4 semineferous tubules (70cm long tubules, site of spermatogenesis)
- lobules feed into rete testis (tubular network on posterior aspect of testis, drains into epididymis)
What are the layers of the testes?
Tunica albuginea (inner layer)
- tough fibrous inner capsule
- creates septa that divides testes into lobules
Tunica vaginalis (outer layer)
- develops from peritoneum
- visceral and parietal layers separated by peritoneal cavity
What are the 4 different cell types in the testes?
Spermatogenic cells:
- produce 100 million sperm cells daily
- located in semineferous tubules
Sustentacular (Sertoli) cells:
- support spermatogenic cells
- nourish developing sperm
Interstitial endocrine (Leydig) cells: - produce androgens (mostly testosterone)
Myoid cells:
- contract rhythmically
- squeeze sperm and fluids out of semineferous tubules
Which cells are responsible for the production of sperm?
Spermatogenic cells (in the semineferous tubules in the testes) produce 100 million sperm cells daily
What is the arterial and venous supply of the testes?
Arterial:
- testicular arteries (from abdo aorta L2)
Venous:
- pampinform plexus
- travels in spermatic cord
- drains into testicular veins
What is the innervation of the testes?
SNS: T10-11
PNS: CNX Vagus
visceral afferent fibres
What is the scrotum?
- an external outpouching of skin, fascia and muscle
- contains the testes, epididymis, and distal ends of spermatic cord
What is the function of the scrotum?
- controls temperature of testes for optimum spermatogenesis (cools by 3 degrees)
Dartos & cremaster muscle:
- relaxation: promotes heat loss
- contraction: prevents heat loss
What are the 6 layers of the scrotum?
(deep to superficial)
- tunica vaginalis
- from an outpouching of the vaginal process peritoneum - internal spermatic fascia
- continuation of transversalis fascia - cremaster fascia
- continuation of IO aponeurosis - cremaster muscle
- originates from IO
- raises testes - external spermatic fascia
- continuation of EO aponeurosis - skin and superficial fascia
- contains dartos muscle (wrinkles skin of scrotum)
Which layers of the scrotum are continuations of the transversalis fascia, EO and IO?
- internal spermatic fascia = continuation of transversalis fascia
- cremaster fascia = continuation of IO aponeurosis
- cremaster muscle = originates from IO
- external spermatic fascia = continuation of EO aponeurosis
What is the arterial and venous supply of the scrotum?
Arterial:
- scrotal arteries (from internal and external pudendal arteries)
- branches from testicular and cremasteric arteries
Venous:
- scrotal veins, draining into pudendal veins
What is the lymphatic drainage of the scrotum and testes?
Scrotum:
- superficial inguinal lymph nodes
Testes:
- lumbar and pre-aortic nodes
What is the innervation of the scrotum?
Anterior scrotal nerves:
- from ilioinguinal (L1) and genitofemoral (L1-2)
Posterior scrotal nerves:
- from superficial perineal (S2-3) and posterior femoral cutaneous (S2-3)
What is the epididymis?
- a highly convuluted tubule (7m long) on posterior surface of testes
- has a head with efferent ductules, body and tail connecting to vas deferens
- connect rete testis to vas deferens
- sperm travel passively along tube over several days, maturing and becoming capable of fertilization
- epididymis stores sperm until ejaculation
What is the vas deferens?
- a 45cm long muscular tube
- conveys sperm from epididymis to ejaculatory duct
- travels in spermatic cord through inguinal canal
Which two structures combine to form the ejaculatory duct?
The vas deferens (conveying sperm) and the duct of the seminal vesicles (conveying seminal fluid)
- ejaculatory duct travels through posterior prostate and opens into prostatic urethra
What are the seminal vesicles?
- paired glands on the posterior surface of the bladder
- secrete a thick fluid that mixes with sperm to form seminal fluid
- duct of each seminal vesicle joins with vas deferens to form ejaculatory duct
What are the bulbourethral glands?
- paired pea size glands inferior to prostate gland
- each gland has a duct which passes through the perineal membrane with urethra and open into proximal part of spongy urethra in the bulb of the penis
- produce mucous like secretions into the urethra during sexual arousal
- secretions neutralize pH of urine residue in urethra and lubricate tip of penis
What are the components of the penis?
Root:
- fixed to anterior pelvis
- consists of right and left crura and bulb
Crura:
- masses of erectile tissue (left and right)
- attach to ischial rami, and covered by ischiocavernosus mm
- converge to form paired corpora cavernosa in the shaft
Bulb:
- mass of erectile tissue in the midline
- continues as corpus spongiosum in the shaft
- outer surface covered by bulbospongiosus mm
- superior surface penetrated by urethra
Shaft:
- 3 cylindral columns of erectile tissue (corpus spongiosum in midline, 2 x corpus cavernosa laterally)
- corpus spongiosum in midline conveys spongy urethra
- contained within a fibrocartilaginous capsule
Glans:
- head of the penis
- expansion of corpus spongiosum
- external urethral orifice exits at tip of glans
- covered by a double layer of skin (prepuce / foreskin)
- corona of glans = crown of penis
Which structures become the corpus spongiosum and corpus cavernosum in the shaft of the penis?
Corpus spongiosum (midline) from bulb of penis
Corpus cavernosa (paired laterally) from right and left crura
What is the arterial and venous supply of the penis?
Arterial:
- branches of internal pudendal artery (from internal iliac artery)
Venous:
- cavernous spaces drain into venous plexus and deep dorsal vein of penis, then prostate venous plexus
- superficial coverings drain into superficial dorsal vein then external pudendal vein
What is the nervous supply of the penis?
ANS:
- SNS: T12-L2
- PNS: pelvic splanchnic (S2-4)
- visceral afferents
Somatic sensory to most of penis; and motor supply to bulbospongiosus and ischiocavernosus:
- pudendal (S2-4) and dorsal nerve of penis (terminal nerve of pudendal)
Somatic sensory to root of penis:
- branches of ilioinguinal nerve (L1)
